Cellulosic structure and method for preparing same



May 12, 1942- T. G. FINZE'L 2,282,568

' CELLULOSIC STRUCTURE AND METHOD FOR PREPARING SAME Filed Oct. 5,' 19387582022 6. 77225 INVENTOIL .IAT-TORNEY Patented May 12, 1942 CELLULOSICSTRUCTURE AND METHOD FOR PREPARING SAME Theron G. Finzel, Kenmore, N.Y., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., acorporation of Delaware Application October 5, 1938, Serial No. 233,484

26 Claims.

This invention relates to artificial fibers, filaments or the like andyarns, threads, cords or the like composed of artificial fibers andfilaments, and methods for producing same. More particularly, it relatesto threads, yarns, cords or the like composed of artificial fibers,filaments, or the like having a unique, random crimp and improvedmethods for producing such structures. The invention is particularlyapplicable and has exceptional utility in the formation of curls andcrimps in thermoplastic cellulosic filaments and yarns.

It has been recognized for some time that the Warmth of wool is duemainly to the air spaces entrapped between adjacent fibers and also dueto the ability of these fibers to maintain such air spaces even afterthe fabrics composed thereof have been subjected to water-wetting and/ormechanical forces. The ability of wool in this regard is largelytraceable to the decided crimp inherently present in wool, particularlyof the finer high grade types. In contrast yarns, composed of artificialfibers or filaments such as cellulose acetate rayon, viscose rayon, orcuprammonium rayon, by virtue of the fact that they normally are spununder tension, are silk-like and possess straight filaments which aredevoid of any crimp or curl.- Accordingly, it has been reasonedlogically that in order to impart a woollike warmth characteristic toartificial fibers, it would be necessary to insert a curl or crimp inthe same.

Numerous methods for imparting curls or crimps to yarns composed ofartificial filaments have lzcen proposed prior to this invention.However, great difiiculty has attended the impartation of a curl orcrimp which will be substantially permanently retained by the filamentswithout objectionably degrading the same. Prior methods for crimping orcurling yarns and filaments have failed due to the impartation of thecurls and crimps in a state of stress and strain and consequently anabnormal or unstable condition. Under such conditions, of course, thepermanency of the crimp is not altogether satisfactory, since naturallythe crimped yarn tends to revert to a normal straight yarn in order torelieve the stress and strain.

An object of this invention is to provide a crimped yarn composed ofcrimped artificial filaments or fibers in which the crimped conditionrepresents essentially the natural or normal state, free from stress andstrain, so that change of such kink or crimp to a straight conditionrepresents to a certain extent a condition of stress and strain.

Another object is to provide a yarn composed of crimped, artificialfilaments in which the crimp is relatively more permanent and lesseasily removed than a crimp imparted by mechanical means.

A further object is to provide a yarn composed of crimped, artificialfilaments character- I textile fabrics, particularly of the pile fabrictype,

that possess an increased fullness. v

A still further object is to provide the crimped yarn of the inventionin the form of a contin-' uous filament yarn.

A specific object is to provide a thermoplastic, cellulosic yarn havingthe permanency and type of crimp described in the above objectives.

A more specific object of the invention is to provide a relativelyeffective and economical procedure of accomplishing the above objects.

Other objects of the invention will appear hereinafter.

The crimped yarn of the invention is prepared by a process comprisingimpregnating a yarn composed of artificial fibers or filaments with asubstance capable of vaporizing rapidly when heated to a suitabletemperature below the melting point of the yarn, suddenly contacting theimpregnated yarn, while maintaining the same free from tension and thuspermitting it to shrink freely, into a hot bath consisting of a liquidnonsolvent for the yarn and thereby removing rapidly substantially allthe vaporizable substance from the yarn whereby a crimp issimultaneously imparted to the filaments which crimp is also exhibitedby the yarn.

The invention will be more clearly apparent by reference to thefollowing detailed description taken in connection with the accompanyingillustrations, in which;

Figure 1 is a diagrammatic illustration of one form of apparatus adaptedto carry out the process of this invention. I

Figure 2 is a highly magnified view showing a yarn which has beensubjected to the crimping process of this invention.

In the illustrations reference numeral 5 designates a cake of yarncomposed of artificial filaments which has been impregnated orconditioned with a vaporizable liquid in a. manner hereinafter to bedescribed. The yarn 6 is removed from the bobbin 5 by means ofpositively driven feed rolls 1, 8, and. 9. The thread passes from thefeed rolls into a tank containing a liquid high boiling non-solvent forthe yarns. The liquid is maintained at a temperature below the meltingpoint of the yarn but at least 30 above the boiling point of thevaporizable liquid with which the yarn has been treated. The yarn 6 isremoved from the tank In by means of positively driven feed rolls ll,l2, and I3. The yarn, 'during its contact with the hot liquid ismaintained free from any tension so as to permit free shrinkage of theyarn.

A large number of deep, irregular crimps projecting in all directions isimparted to the filaments of the yarn. The speed of feed rolls 1, 8, and9 and the speed of feed rolls H, l2,

and I3 may be so adjusted as to continuously maintain a section of theyarn in free coils within the hot liquid. The yarn is passed from feedrolls II, I2, and I3 into a collecting can I 4 or the like where it iscollected in loose coils without imparting tension thereto.

After the yarn 6 has been subject to the abovedescribed crimpingoperation, the filaments 6a will exhibit individual crimps which are outof phase with each other as shown in Figure 2.

In the preferred embodiment of the invention a substantially untwistedthermoplastic cellulosic yarn composed of a plurality of filaments istreated so as to give the filaments deep, random, and irregular crimpsthat represent a normal, stable condition. This may be accomplished inthe following manner. The thermoplastic yarn is impregnated orconditioned with a vaporizable liquid having an atmopheric boiling pointat least 30 C. lower than the temperature of the hot crimping bath. Inthe case of a relatively water-soluble vaporizable liquid, includingwater, the thermoplastic yarn is conditioned in contact with thesaturated vapors thereof until the yarn has sorbed an amount equal tobut not exceeding "a saturated equilibrium sorption condition at thetemperature of the yarn immediately prior to introduction into the hotcrimping bath. In the case of a relatively water-insoluble butoil-soluble vaporizable liquid, such as heptane, the yarn is conditionedin contact either with the saturated vapor and/or with the liquid. Theconditioned yarn is introduced quickly, while maintaining it free fromtension and free to shrink, into a hot liquid crimping bath comprising ahigh boiling nonsolvent for the yarn. The bath should have a temperaturesomewhat below the melting point of the yarn and at least 30 C. abovethe boiling point of the vaporizable liquid employed to condition theyarn. In the case of a continuous yarn, the rate at which the yarn isfed into the crimping bath may be 5% to 60% faster than the rate theyarn is withdrawn. Upon introduction into the crimping bath, the yarnimmediately softens somewhat, and the vapor formed in situ from thevaporizable liquid is emitted steadily and rapidly as small bubbles atrandom from and/or through certain parts of the yarn surface. Duringemission of the -vapors the yarn and the constituent filaments in thefilaments after insertion of the crimp is removed by permitting the yarnto remain in the crimping bath for a very short time after the vaporshave apparently all been driven from the yarn. The total time duringwhich the yarn is permitted to remain in the crimping bath may varywidely depending upon the chemical composition of the yarn, thecomposition and method of the vaporizable substance with which the yarnis treated, the composition and temperature of the crimping bath, andpossibly for other reasons. As a general rule,- however, the total timeof contact with the crimping bath should be not substantially less thanof a second and not more than 180 seconds. The crimped yarn is removedundersub'stantially no tension from the crimping bath. The yarn isallowed to cool in a relaxed condition to room temperature in order toset the crimp to a condition that the crimped form is a normal stableone, substantially free from stress and strain.

The following examples illustrate certain specific applications of theinvention, it being understood, of course, that they are not to beconstrued as being restrictive of the scope of the invention:

Example I Untwisted, 10 denier per filament cellulose acetate yarnhaving a combined acetic acid content of about 54% is conditionedseveral days at room temperature in an atmosphere of high relativehumidity (65% to R. H.) until no further gain in moisture content isobserved. The conditioned yarn is entered quickly but loosely into alight mineral oil bath which is held at a temperature between C. and 220C. Upon entrance into the oil bath, the yarn becomes softened andsomewhat plastic and the moisture in and on the yarn is rapidlyvaporized. The rapid and steady issuance of vapor at random from thesurface of the yarn causes the filaments to warp and bend irregularlyand a crimp results. After the moisture has been entirely driven fromthe yarn, the crimped yarn in its plastic condition is maintained incontact with the hot bath for a second or so longer in order to relieveall internal strains. In order to maintain the yarn in a loose conditionin the oil bath, the feed rate of yarn into the bath is 10% to 25%greater than the rate of yarn take-off from the bath and in order tohave suflicient time for driving off all the moisture and for heatingthe yarn slightly thereafter, the length of the bath is such as to givea yarn contact with the bath of approximately 2 to 3 seconds. Afterwithdrawal from the bath, the yarn is allowed to cool in order to setthe crimp. If desired, the oil is extracted from the yarn with suitableliquids such as toluene, trichlorethylene, or other dry cleaning agents.The oil may also be removed by scouring the yarn with of Gardinol orsoap solution at 75 C. to 85 C. After rinsing, the yarn is allowed toair dry. As measured on the dry yarn, the crimp inserted in thefilaments by the oil bath amounts to 15 to 30 crimps per inch and notonly is irregular as to form-of the crimp, but also is distributed in arandom manner along the length of the filaments. The crimped yarn issoft and bulky and has a desirable hand.

Example II Instead of white mineral oil, olive oil heated to to 200 C.may be used in the same manner as disclosed in Example I. If desired,the olive oil remaining on the yarn after the crimping treatment neednot be completely removed,

Example III A pile fabric, the pile of which consists largely ofcellulose acetate fibers, is conditioned for several days at roomtemperature in an atmosphere having a humidity of nearly 100% R. H.until no 1 further gain in moisture content is observed. The

thus humidified fabric is immersed for about 2 seconds in a bath ofwhite mineral oil held at a temperature between 180 and 220 C. Afterremoving the fabric from the oil bath and allowing it to cool, theresidual oil in the fabric is extracted by means of organic solventssuch as toluene or dry cleaning fluid.

By virtue of the oil bath treatment, the fibers of the pile of thetreated fabric are crimped and because of their crimped conditionsupport each other to a large extent in an erect position and, inconsequence, present more of a brush effect than similar but untreatedfabric. also is more full and more crush-resistant than an untreatedpile fabric.

Example IV Cellulose acetate staple fibers of, for instance, 5.5 denieror denier per filament are conditioned in a loose and open state overwater, at room temperature for several days so as to absorb as muchmoistureas possible without condensation of free water on the fibers.The moisturecontaining staple fibers in a loose and fiuffy physicalcondition are immersed for 2 to 4 seconds in a mineral oil bath that isheld at .a temperature of 180 to 220 C. The 2 to 4 seconds contact ofthe fibers with the bath vap'orizes ofi completely the moisture in thefibers and imparts a high degree of crimp. After' withdrawal from thebath, the oil is removed from the staple fibers by centrifuging andsubsequent extraction with organic solvents such as toluene or'petroleum type solvents. The resulting crimped fibers possess adesirable appearance and feel.

Example V Example VI Untwisted viscose rayon yarn composed of aplurality of filaments, the filament denier 'of which is approximately10, is-immersed for several hours in water at room temperature. The wetyarn is passed through a pair of rubber squeeze rolls to remove theexcess of water and then is entered rapidly in a hot mineral oil bath,the temperature of which is 190 to 220 C., and preferably 210 C.Substantially all the water in the yarn issues as steam which softensthe yarn and warps the individual filaments thereof and yields a deepcrimp therein. The length of time of contact of the yarn with the oilbath is The fabric 3 approximately 1 to 3 seconds, which permits thecrimp to be inserted and permits also slight afterheating of the yarn toincrease the stability of the crimp. After withdrawing the yarn withouttension from the oil bath, the yarn is cooled and the oil is removedfrom the yarn in a manner described previously in the above examples.The resulting oil-free and dry viscose rayon yarn possesses a verydefinitely crimped condition an has a desirable appearance and hand.

Example VII Untwisted gel viscose rayon yarn composed of a plurality offilaments, having a denier of about 10, which has been regenerated,desulfured, bleached, washed, but never dried, is submerged for 1 to 3seconds in a mineral oil bath held at a temperature of 180 to 210 C.After withdrawal under no tension from the oil bath, the yarn is cooledand the oil is removed in the usual way.

The resulting yarn is highly crimped and has an appearance similar tothat described in Example VI. I

The yarns may be impregnated or conditioned with volatilizable materialsof many kinds and the specific selection will depend on factors such asthe base material of the particular artificial yarn and the temperatureof the crimping bath.

The process will operate if the volatilizable or bath. In the case ofliquid volatilizable conditioning agents, it is preferred that theliquid have a boiling point at least about 30 C. below the temperatureof the crimping bath, and therefore at least about 30 C. below themelting point of the yarn treated. For instance, inthe case of certaincellulose acetate yarns, it is desirable that the volatilizable liquidhave a boiling point below 150, and more preferably under 115 C. In thecase of conditioning a thermoplastic yarn, such as cellulose acetate,with a volatilizable liquid such as water, it is preferred that the yarnbe impregnated by contact with the vapors of the liquid rather than bydirect contact with the liquid. In

the case of water, the cellulose acetate yarn preferably is exposed atthe temperature the yarn will have immediately prior to entrance intothe crimping bath to an atmosphere of at least 30% R. H., and morepreferably to R. H., until the equilibrium amount of moisture has beensorbed by the yarn. The cellulose acetate yarn, however, may beconditioned directly in contact with water, provided all water in excessof the equilibrium amount described in the preceding sentence is removedprior to immersion of the yarn in the crimping bath. In general,cellulose acetate yarn which is conditioned in an atmosphere therelative humidity of which is lower than 95% to 100% can be subjected toa higher temperature in the subsequent oil treatment than thoseconditioned at 100% R. H. In the case of conditioning liquids of thewater-insoluble type,

izable materials which can be used for conditioning cellulose acetateyarn and the results obtained when the yarn is conditioned by contactwith the liquid and vapor formof the material. The table also describesthe crimping bath temperature ranges which are suitable with each typeof conditioning.

' Crimping bath Crimping bath tempcratemperatures for Conditioning agenttures {or yarn condiyarn conditioned tioned in the liquid in vapor overthe liquid Isopropyl alcohol..... 115-200 C. (fibers slight- 1l5200 C.(d-

ly wea bers strong). Methyl alcohcl.....-.. l-200 C. (fibers weak).115-185 C. Carbon tetrachloride. l35-200 C... 135-210 C Toluene l502l0C- l752l0 C Benzene 150-200 C--. 150-200 C Heptane l652l5 C 165-2l5 Ckcrtiii 1sllcilduni. Dissolves yarn l40l75 C U o e y 6110 g Y o 58; ..do115-210 C. o ace one. o 20% }....d0 170-200 0. Water L 120-140 C 180220C.

' to prevent condensation of liquid water on the cellulose acetate yarnif it is planned to use a high crimping bath temperature.

The optimum amount of volatilizable material position of the yarn andthe crimping bath temperature used in driving out the volatilemaaterial. Cellulose acetate can best be conditioned, for example, byallowing it to absorb an equilibrium amount of moisture from anatmosphere of 95% to 100% R. H. at room temperature immediately afterwhich the yarn is immersed in a hot oil crimping bath ata' temperatureof 180 to 220 C.

Liquid materials other than mineral oil may be used as the heatin mediaof the crimping bath. The prime requisites for such a liquid materialare that it should be substantially inert to the yarn treated, i. e., itshould not swell, dissolve, or attack the yarn treated; it should not beunduly volatile at the temperature of treatment; it should not dissolvethe vapor liberated from the yarn to any appreciable extent at thetemperature of treatment; and-it should be easily removed from the yarnafter the yarn treatment. Accordingly, the choice of the material forthe bath will depend largely upon the composition and type of yarn beingtreated and the temperature to be employed for the crimping. Bearingsuch factors in mind, the selection may be made from such materials aschlorinated diphenyl,

chlorinated naphthalene, diphenyl, ethyl sebacate, olive oil, corn oil,castor oil, cottonseed oil, mineral oil, and metallic baths such asWoocls metal or mercury.

The temperature of the crimping treatment may vary from approximately115 C. to 250 C., or even wider, depending upon the kind of volatilematerial absorbed by the fibers before treatment in the hot bath andalso upon the chemical nature of the yarn. In general, it is necessary2,282,568 liquid. The following table discloses some volatil in the caseof thermoplastic yarn that the temperature'oi the crimping bath besomewhat below the melting point of the yarn and at least C. higher thanthe boi ing point of the volatilizable or vaporizable conditioningmaterial. In the particular case of cellulose acetate yarn, the lowerthe combined acetic acid content, the higher may the temperature of thecrimping bath be, since the melting point of the yarn is somewhat higherand since the yarn may tolerate more moisture. Cellulose acetateyarn-having a combined acetic acid content of 51.2% can be successfullycrimped at 240 C.

The manner in which the conditioned yarns are subjected to the hot bathtreatment is extremely important. In the crimping bath it is necessaryto secure an extremely rapid heat transfer between the heating mediumand the yarn in order to produce the vapors in situ and emit the same assmall bubbles in a steady, rapid rate, but at random, from thesurface ofthe yarn. Generally, the conditioned textile yarn is immersed quicklyand passed through the hot oil crimping bath while maintained free fromany tension and, therefore free to shrink, and withdrawn from the bathunder little, if any, tension. In the case of conditioned fibers such asstaple lengths, it is important that they be placed loosely in the bathheldby the yarn depends upon the base comand in an open condition, sothat they are in a position to shrink and crimp freely. The time ofcontact with the bath, as above described, is generally about of "asecond to seconds. It is desirable to have the yarn in contact with theoil bath for a sufiicient period to insert the desired degree of crimp,but it is undesirable to have the yarn in contact With the bath toolong, as such promotes a weakening, embrittlement, discoloration, andcharring of the yarn. It is also preferred to maintain the yarn incontact with the crimping bath for a sufiicient period of time to notonly drive off substantially all the volatilizable material, but also toafter-heat for a very short time to remove any strained condition.

The most desirabl manner of removing the crimping medium, after thetreatment, especially if an oil bath is employed, is to extract the oilor oily material with toluene or a petroleum fraction such as drycleaners liquid, which will dissolve the oil or oily substance and notaffect the crimped yarn. Boil-oil methods with soap or Gardinol (sodiumsalts of higher fatty alcohol sulfates) may be utilized, but theefiiciency of oil contrast to the smooth rayon and silk yarn.

Such rough crimped yarns abraid very easily and tear readily unlessproperly sized. Any suitable sizing solution which is used in the artfor sizing bulky threads to permit their use in textile operations maybe employed.

In the above specification, reference has been to cellulose acetate yarnas the thermoplastic artificial yarn. It will, of course, be recognizedthat the invention may also be applied to secure crimped yarns composedof other thermoplastic maintaining the same free from tension, with aliquid non-solvent for said filaments, said liquid having a sufiicientlyelevated temperature to quickly volatilize said volatilizable material,and cause said filaments to crimp while in contact therewith, saidvolatilizable material having a boiling point at least 30 C. below thetemperature of said liquid non-solvent.

4. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises applying to suchstructures comprising artificial filaments a volatilizable material, andthen contacting said structures, -while maintaining the same free fromtension, with a liquid non-solvent for said filaments, said liquidhaving a temperature below the melting point of said structures but saidtemperature being sufficiently elevated to quickly volatilize saidvolatilizable material and cause said filaments to crimp while incontact therewith, said volatilizable material having a boiling point atleast 30 C. below the temperature of said liquid nonsolvent.

5. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises applying to suchstructures comprising artificial filaments vapors of a volatilizablematerial, and then contacting said structures, while maintaining thesame free from tension, with a liquid non-solvent for said filaments,said liquid having a sufiiciently'elevated temperature to quicklyvolatilize said volatilizable material and cause said filaments to crimpwhile in contact therewith.

6..The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially-weakening the filaments which comprises applying to suchstructures comprising artificial thermoplastic filaments vapors of avolatilizable material, and then contacting said structures, whilemaintaining the same free from tension, with a liquid non-solvent forsaid filaments, said liquid having a sufliciently elevated temperatureto quickly volatilize said volatilizable material and cause saidfilaments to crimp while in contact therewith.

7. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises applying to suchstructures comprising arcause said filaments to crimp while in contacttherewith.

9. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises applying to suchstructures comprising artificial filaments vapor of a volatilizablematerial, and then contacting said structures, while maintaining thesame free from tension, with a liquid non-solvent for said filaments,said liquid havlng a temperature below the melting point ofsaidstructures but said temperature being sulficiently elevated to quicklyvolatilize said volatilizable material and cause said filaments to crimpwhile in contact therewith.

10. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises applying to suchstructures comprising artificial filaments vapors of a volatilizablematerial, and then contacting said structures, while maintaining thesame free from tension, with a liquid non-solvent for said filaments,said liquid having a temperature below the melting point of tificialthermoplastic cellulosic filaments vapors of a volatilizable material,and then contacting said structures, while maintaining the same freefrom tension, with a liquid non-solvent for said filaments, said liquidhaving a sufiiciently elevated temperature to quickly volatilize saidvolatilizable material and cause said filaments to crimp while incontact therewith.

8. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, stantially weakening the filamentswhich comprises applying to such structures comprising cellulose acetatefilaments vapors of a volatilizable material, and then contacting saidstructures, while maintaining the same free from tension,

with a liquid non-solvent for said filaments, said liquid having asufiiciently elevated temperature to quickly volatilize saidvolatilizable material and irregular crimps without subsaid structuresbut said temperature being suf ficiently elevated to quickly volatilizesaid volatilizable material and cause said filaments to crimp while incontact therewith, said volatilizable material having a boiling point atleast 30 C. below the temperature of said liquid nonsolvent.

11. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises subjecting suchstructures comprising artificial filaments to an atmosphere having arelative humidity of at least 30%, until the moisture content of thestructures comes to equilibrium, and then contacting said structures,while maintaining the same free from tension, with a liquid non-solventfor said filaments, said liquid having a sufiiciently elevatedtemperature to quickly volatilize said moisture content of thestructures and cause said filaments to crimp while in contact therewith.

12. The method 'of producing threads, yarns, fabrics, and likestructures comprising filaments exhibiting deep, irregular. crimpswithout substantially weakening the filaments which. comprisessubjecting such structures comprising artificial thermoplastic filamentsto an atmosphere 7 having a relative humidity of at least 30%, un-

til the moisture content of the structures comes to equilibrium, andthen contacting said struc--' tures, while maintaining the same freefrom tension, with a liquid non-solvent for said filaments, said liquidhaving a sufliciently elevated temperature to quickly volatilize saidmoisture content of the structures and cause said filaments to crimpwhile in contact therewith.

13. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises subjecting suchstructures comprising artificial thermoplastic cellulosic filaments toan atmosphere having a relative humidity of at least 30%, until themoisture content of the structures comes to equilibrium, and thencontacting said structures, while maintaining the same free fromtension, with a liquid non-solvent for said filaments, saidliquid havinga a very definite and desirable depth "and lofty materials such ascellulose acetate propionates, cellulose" acetate butyrate, and othersimple and mixed aliphatic acid esters of cellulose; as well as methylcellulose, ethyl cellulose, propyl celluose, butyl cellulose, and otherorganic ethers of cellulose; as well as yarns composed of vinyl acetateresins, vinyl acetal resins, vinyl chloride-vinyl acetate interpolymerresins, and other vinyl resins. Obviously, also the artificial materialsto be crimped'may contain within reason plasticizers, pigments, dyes,and other modifiers. Additionally, while perhaps of less interest, theinvention may be applied to other cellulosic artificial yarns such asthe regenerated cellulose type derived in the viscose and cuprammoniumprocess. Because regenerated cellulos yarn is not therm plastic. certainslight changes may be made in the process of the invention as comparedto cellulose acetate yarn. For instance, in the case of regeneratedcellulose yarn, the temperatures of the crimping bath can be increasedconsiderably in many cases. Likewise, the specific choice of thevolatilizable material may be somewhat different from that for celluloseacetate Yarn. Additionally, the regenerated cellulose yarn in the caseof water, can be humidified by exposure to a moist atmosphere or it maybe soaked directly in water and the excess liquid water removed byshakin and the yarn crimped in the hot oil bath at a, temperature of 180to 220 C. All these slight differences, however, are considered to bewell within the province of one skilled in the art.

The filament'denier of the cellulose acetate yarn, as well asregenerated cellulose rayon yarn, has a very definite effect on thedegree of crimp obtained. It has been found that filaments of heavydenier showed a most pronounced crimp. For instance, the degree of crimpof a 10 denier filament is greater than that of the 5.5 denier which, inturn, is greater than that of a 3 denier filament.

In the above specification any reference to an untwisted yarn is meantto include yarn having a very slight twist, for example, not more thantwo turns per inch whereby to hold the filaments together, as well asyarn having no twist. The term yarn in the present specification isintended to include yarn of continuous length and composed of individualcontinuous filaments, or yarn in which some of the filaments have beencut, or yarn cut to form filaments of staple length or other obviousmodifications. The term crimp as used in the present specification ismeant to include crimps, curls, undulations or other abrupt bends in thefilaments and/or yarns.

By means of the present method a decided and accentuated crimp isimparted to the straight hand.

It will be understood that the crimping process I of the presentinvention may be combined with filaments and at the same time, allstrains are relieved and the crimped filaments are set in their new andcrimped form in a state in which the crimped form is normal and stable,while the straight condition is abnormal. The crimped yarns are thus putinto a condition wherein more force is necessary to pull them out to astraight condition than necessary with filaments curled by mechanical orsimilar methods. The crimped yarns obtained in accordance with mymethods disclosed herein are lofty in appearance and show a greaterresistance to crushing than yarns curled by mechanical means. The yarnspossess a realtively large number of fine and irregularly placedundulations or crimps per inch of length so that the yarns show goodcovering power and the fabrics produced therefrom show other methods ofcrimping to produce crimped filaments, threads, and the like having acomposite crimp. Thus, in addition to imparting crimp according to thenovel procedure described above, a further crimp can be imparted whichmay be either of a greater or less degree than the crimp which has beenimpe rted by the oil crimping procedure. In following this modification,it is preferred that the second crimp be greater in degree, that is,less crimps per inch than the crimps produced by the oil crimpingprocess. The oil crimping process of this invention can be supplemented,for example, by passing the yarn after it has been crimped by the oilcrimping process, and preferably before the oil has been removed andwhile the yarn is still hot, through a crimping device such as isillustrated in Stone et al., Patent No. 1,973,581, issued September 11,1934. Fabrics produced from yarns crimped in this manner have morefullness and bulk than fabrics composed of yarn which has been subjectedonly to the oil crimping process. It is understood, of course, that inthis modification of the invention, reference to crimping with oil isillustrative and that in place of oil, the other equivalents of oilmentioned in this specification may, of course, be used.

Since it is obvious that many changes and modifications can be made inthe above-detailed description without departing from the nature andspirit of the invention, it is to be understood that the invention isnot to be limited except as set forth in the appended claims.

I claim:

1. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises applying to suchstructures comprising artificial thermoplastic filaments .avolatilizable material, and then contacting said structures, whilemaintaining the same free from tension, with a liquid non-solvent forsaid filaments, said liquid having a sufficiently elevated temperatureto quickly volatilize said volatilizable material, and cause saidfilaments to crimp while in contact therewith, said volatilizablematerial having a boiling point at least 30 C. below the temperature ofsaid liquid non-solvent.

2. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises applying to suchstructures comprising artificial thermoplastic cellulosic filaments avolatilizable material, and then contacting said structures, whilemaintaining the same free from tension, with a liquid non-solvent forsaid filaments, said liquid having a sufiiciently elevated temperatureto quickly volatilize said volatilizable material, and cause saidfilaments to crimp while in contact therewith, said volatilizablematerial having a boiling point at least 30 C. below the temperature ofsaid liquid non-solvent.

3. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises applying to suchstructures comprising cellulose acetate filaments a volatilizablematerial, and then contacting said structures, while sufiicientlyelevated temperature to quickly volatilize said moisture content of thestructures and .cause said filaments to crimp while in contacttherewith.

liquid having asufiiciently elevated temperature to quickly volatilizesaid moisture content of the structures and cause said filaments tocrimp while in contact therewith.

15. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises subjecting suchstructures comprising artifical filaments to an atmosphere having arelative humidity of at least 30%, until the moisture content of thestructures comes to equilibrium, and then contacting said structures,while maintaining the same free from tension, with a liquid non-solventfor said filaments, said liquid having a temperature below the meltingpoint of said structures but said temperature being suflicientlyelevated to quickly volatilize said moisture content of said structuresand cause said filaments to crimp while in contact therewith.

16. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which com prises subjecting suchstructures comprising artificial filaments to an atmosphere having arelative humidity of at least 30%, until the moisture content of thestructures comes to equilibrium, and then contacting said structures,while maintaining the same'free from tension, with an oil which issubstantially inert to said filaments, said oil having a suflicientlyelevated temperature to quickly volatilize said moisture content of thestructures.

1'7. The method of producing threads, yarns, fabrics, and likestructures comprising filaments exhibiting deep, irregular crimpswithout substantially weakening the filaments which comprises subjectingsuch structures comprising artificial thermoplastic filaments to anatmosphere having a relative humidity of at least 30%, until themoisture content of the structures comes to equilibrium, and thencontacting said structures, while maintaining the same free fromtension, with an oil which is substantially inert to said filaments,said oil having a sufficiently elevated temperature to quicklyvolatilize said moisture content of the structures.

18. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantiallyweakening the filaments which comprises subjecting suchstructures comprising artificial thermoplastic cellulosic filaments toan atmosphere having a relative humidity of at least 30%, until themoisture content of the structures comes to equilibrium, and thencontacting said structures, while maintaining the same free fromtension, with an oil which is substantially inert to said filaments,said oil having a sufiiciently' elevated temperature to quicklyvolatilize said moisture content of the structures.

19. The method of producing threads, yarns, fabrics, and likestructures. comprising filaments exhibiting' deep, irregular crimpswithout substantially weakening the filaments which comprises subjectingsuch structures comprising cellulose acetate filaments to an atmospherehaving a relative humidity of at least 30%, until the moisture contentof the structurescomes to equilibrium, and then contacting saidstructures,

while maintaining the same free from tension, with an oil which issubstantially inert to said filaments, said dil having a sufficientlyelevated temperature to quickly volatilize said moisture content of thestructures.

20. The method of producing threads, yarns,

fabrics, and like structures comprising filaments exhibiting deep,irregular crimps without substantially weakening the filaments whichcomprising subjecting such structures comprising.

artificial filaments to an atmosphere having a relative humidity of atleast 30%, until the moisture content of the structures comes toequilibrium, and then contacting said structures, while maintaining thesame free from tension, with an oil which is substantially inert to saidfilaments, said oil having a temperature below the melting point of saidstructures but said temperature being sufi'iciently elevated to quicklyvolatilize said moisture content of said structures.

21.'The method of producing threads, yarns,- fabrics, and likestructures comprising filaments exhibiting deep, irregular crimpswithout substantially weakening the filaments which comprises subjectingsuch structures comprising artificial filaments to an atmosphere havinga relative humidity of between 95% and 100% until the moisture contentof the structures comes to equilibrium and then immersing saidstructures, while maintaining the same free from tension, into a bath ofoil which .is substantially inert to said structures, said oil bathhaving a sufiiciently elevated temperature to quickly volatilize saidmoisture content of the structures.

22. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises subjecting suchstructures comprising artificial thermoplastic filaments to anatmosphere having a relative humidity of between 9 and 100% until themoisture content of the structures comes to equilibrium and theniminersing said structures, while maintaining the same free fromtension, into a bath of oil which is substantially inert to saidstructures, said oil bath having a sufiiciently elevated temperature toquickly volatilize said moisture content of the structures.

23. The method. of producing threads, yarns, fabrics, and likestructures comprising filaments exhibiting deep, irregular crimpswithout 'substantially weakening the filaments which comprisessubjecting such structures comprising artificial thermoplasticcellulosic filaments to an atmosphere having a relative humidity ofbetween and until the moisture content of the structures comes toequilibrium and then immersing said structures, while maintaining thesame free from tension, into a bath of oil which is substantially inertto said structures, said oil bath having a sufficiently elevatedtemperature to quickly volatilize said moisture content of thestructures.

24. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps. withoutsubstantially weakening the filaments which comprises subjecting suchstructures comprising, cellulose acetate filaments to an atmospherehaving a relative humidity of between 95% and 100% until the moisturecontent of the structures comes to equilibrium and then immersing saidstructures, while maintaining the same free from tension, into a bath ofoil which is substantially inert to said structures, said oil bathhaving a sufiiciently elevated temperature to quickly volatilize saidmoisture content of the structures.

25. 'The method of producing threads, yarns, fabrics, and likestructures comprising filaments exhibiting deep, irregular crimpswithout substantially weakening the filaments which comprises subjectingsuch structures comprising artificial filaments to an atmosphere havinga relative humidity of between 95% and 100% until the moisture contentof the structures comes to equilibrium and then immersing saidstructures, while maintaining the same free from tension, into a bath ofoil which is substantially inert to said structures, said oil-bathhaving a temperature below the melting point of said structures but saidtemperature being sufiiciently elevated to quickly volatilizesaid-moisture content of said structures.

26. The method of producing threads, yarns, fabrics, and like structurescomprising filaments exhibiting deep, irregular crimps withoutsubstantially weakening the filaments which comprises subjecting suchstructures comprising artificial filaments to an atmosphere having arelative humidity of between and until the moisture content of thestructures comesto equilibrium and then immersing said structures, whilemaintaining the same free from tension, into a bath of oil which issubstantially inert to said structures, said oil bath having asufficiently elevated temperature to quickly -volatilize said moisturecontent of the structures, and maintaining the structures in contactwith said bath until after all of the moisture has been volatilizedtherefrom.

- THEROIjI G. FINZEL.

